The objective of the proposed research is to develop a starch gel electrophoretic system for the separation and identification of mammalian enzymes hydrolyzing ribonucleic acid. The zymorgram technique will be used in this project. Two types of staining system will be used to detect enzymatic activity in starch gels. The first staining system contains a-napthyl derivatives of nucleotides as the substrate, and diazonium salts. The second staining system contains RNA or di- and tri-nucleotides as the substrate. Different substrates will be used to identify the nuclease isozymes present in tissues and cultured cells. Altered ribonuclease activity has been found in the serum of individual with certain types of cancer and kidney disease. The techniques developed in this proposal will make it possible to examine many different nuclease isozymes simultaneously, and to identify any changes in the isozyme pattern caused by disease.